The invention relates to a method for mixing two or more materials in granular form, in powder form or liquid, with a viscosity which is or which is not high, in a continuous process in a mixing housing, so that a mixture with a homogenous distribution arises, whereby those materials are introduced into the mixing housing, are mixed therein with the aid of a rudder rotating around an axis, and the mixture is finally expelled from the mixing housing.
Such homogenous mixtures serve, for example, as basic materials for extruding end injection moulding of plastics. The homogeneity of such materials is especially important in cases in which one of the composite materials is a colouring material and a homogenous coloration of the mixture must be achieved.
There are various methods and appertaining devices known in order to achieve the said homogenous mixtures as well as possible. Those methods have in common that those materials are mixed with the aid of a rotating mechanism in a mixing vessel which is filled with the materials concerned, in which they are moved around in the mixing housing in principally a sidle direction. With these methods it is usually not possible to achieve the desired completely homogenous mixture. For example, mixtures of granulates of a plastic and a colouring material will always show the colour in stripes. This is not improved by continuing the mixing process for a longer period of time. On the contrary, in that case a certain separation will even occur in due course as a result of the differences in the densities of the various materials.